Automatic door opening and closing apparatus and refrigerator having the same

ABSTRACT

An automatic door opening and closing apparatus and a refrigerator having the same. The refrigerator includes a cabinet and a refrigerator door hinged to an open side of the cabinet. The opening and closing apparatus comprises a first rotating shaft to rotatably connect the refrigerator door to the cabinet, a damper unit to allow the door to be automatically opened or closed, and a second rotating shaft to rotatably connect the damper unit to the door to allow the door to be automatically opened or closed by the damper unit depending on an opening degree of the door. The damper unit includes a damping member and a link member. The link member has a first end coupled to the damping member, and a second end coupled to the second rotating shaft. The damper unit and other parts of the automatic door opening and closing apparatus show simplified and strong structures, thereby achieving effective and smooth operation of the refrigerator door with a low effort. By allowing the refrigerator door to be automatically opened or closed when the opening angle of the refrigerator is in a predetermined range, the automatic door opening and closing apparatus of the present invention can provide satisfactory use of products.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 2004-34899, filed on May 17, 2004 and Korean Patent Application No. 2005-38566 on May 9, 2005 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an automatic door opening and closing apparatus and a refrigerator having the same, and, more particularly, to an automatic door opening and closing apparatus usable with a refrigerator capable of allowing a refrigerator door to be automatically opened after it reaches a predetermined opening angle and to be automatically closed below the predetermined angle.

2. Description of the Related Art

In general, the interior of a refrigerator is divided into a freezing chamber and a refrigerating chamber. The freezing chamber is used to store foods that should be kept below freezing, such as meat, ice cream, etc. The refrigerating chamber is used to store foods at an appropriate temperature not to freeze the foods, such as vegetables, beverages, etc.

The storage chambers of the refrigerator are generally opened at their front sides to store or remove foods from the storage chambers, and doors are coupled to the open front sides of the respective storage chambers to close them. Each door is pivotally supported by hinge devices, which are mounted at upper and lower portions of the left or right end of a door body, to be opened or closed via pivotal rotation thereof. Generally, the hinge device is connected to an automatic door opening and closing apparatus which can provide smooth opening or closing operation of the refrigerator door. The automatic door opening and closing apparatus is designed to allow the refrigerator door to be automatically opened or closed smoothly within a predetermined range and to be forcibly closed even if the door is incompletely closed to thereby prevent leakage of cold air from the interior of the refrigerator.

In the case of a large capacity refrigerator having a large cabinet, doors hinged to the cabinet are also large and heavy, suffering from a difficulty in opening and closing operations thereof.

The heavy doors, further, have a problem that they may fail to tightly close the refrigerator cabinet due to a shock when they are rushed to the cabinet, resulting in cold air leakage.

As one proposal to solve the above problems, Korean Utility Model Laid-Open Publication No. 91-11734 discloses an automatic door opening and closing apparatus usable with a refrigerator, which performs the opening and closing operations of a refrigerator door using the elasticity of a spring. The disclosed conventional automatic door opening and closing apparatus includes a hinge member and a fixed member which are successively arranged, and a movable member and a spring disposed thereabove. When the refrigerator door is opened, the movable member rotates and slides upward along an inclined lateral surface of a protrusion formed at the fixed member in a state wherein the protrusion is fitted in an opening of the movable member. As the lower surface of the movable member reaches the tip end of the fixed member, the spring is completely compressed, allowing the door to be completely opened. Conversely, as the opened door is pushed to be closed, the movable member rotates and slides downward along the inclined lateral surface of the protrusion of the fixed member by virtue of the elasticity of the spring to thereby be coupled to the fixed member. In this manner, the door is automatically closed.

The conventional automatic door opening and closing apparatus as described above, however, has a problem in that the inclined lateral surface of the fixed member, used to raise the movable member relative to the fixed member, is steep, requiring a relatively large force to open the door.

Further, when an excessive pushing force is applied to the door, the door is rushed to a closing position by using the elasticity of the spring, causing operational noise and damage to the refrigerator. Furthermore, the sliding motion of the movable member tends to deteriorate the performance of the opening and closing apparatus and to generate noise at the sliding contact surfaces of the movable and fixed members.

As another example different from the conventional automatic door opening and closing apparatus as described above, there have been used automatic door opening and closing apparatuses of the type that a coil spring, compensator, etc. are mounted in a cylinder containing oil therein. This kind of opening and closing apparatuses, however, suffer from a problem that air cells provided in the compensator are damaged after extended use, thereby discharging air. If the air is mixed with the oil contained in the cylinder during compression of the automatic door opening and closing apparatus, it generates operational noise.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the invention to provide an automatic door opening and closing apparatus usable with a refrigerator capable of achieving smooth and accurate opening and closing operations of a refrigerator door with a low effort and no operational noise, thereby preventing unnecessary loss of cold air.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

The foregoing and/or other aspects of the present invention are achieved by providing an automatic door opening and closing apparatus usable with a refrigerator including a cabinet and a refrigerator door hinged to an open side of the cabinet, the opening and closing apparatus comprising a first rotating shaft to rotatably connect the refrigerator door to the cabinet, a damper unit to allow the refrigerator door to be automatically opened or closed, and a second rotating shaft to rotatably connect the damper unit to the refrigerator door to allow the refrigerator door to be automatically opened or closed by the damper unit according to an opening degree of the refrigerator door, wherein the damper unit may include a damping member and a link member, and the link member may have a first end coupled to the damping member, and a second end coupled to the second rotating shaft.

The damper unit may further include a casing, having at least three sides, to protect the damper unit from external force.

The link member may have a bent portion, extending from the second end thereof by a length corresponding to a distance between the first rotating shaft and the second rotating shaft, to thereby rotate the door by an opening angle larger than 90°.

The opening and closing apparatus may further comprise a first supporting unit coupled to a surface of the casing, the first rotating shaft being provided at one side of the first supporting unit.

The first supporting unit may includes a bent plate having a first surface coupled to an upper surface of the casing and a second surface coupled to a lateral surface of the casing to thereby prevent the droop thereof due to the weight of the door.

The opening and closing apparatus may further comprise a second supporting unit provided at one side thereof with the second rotating shaft to be rotatably coupled to the second end of the link member, and at the other side thereof with a coupling hole to allow the first rotating shaft to be rotatably inserted therein.

The first supporting unit may have a latch pin located close to the first rotating shaft to be caught by one side of the second supporting unit to thereby adjust the opening angle of the door, and first and second pin holes for the selective fastening of the latch pin, and the latch pin may be inserted in the first pin hole to rotate the door by an opening angle larger than 90°, or may be inserted in the second pin hole to rotate the door by approximately 90°.

The second supporting unit may have a stopper in the vicinity of the coupling hole thereof to catch the latch pin inserted in the first or second pin hole to thereby adjust the opening angle of the door.

A support plate may be provided at a lower surface of the casing and may have coupling holes for the coupling of an adjustor bolt to adjust the installation height of the cabinet.

The damping member may include a cylinder to contain oil and gas, a cap to close a first end of the cylinder, a piston to compress or decompress the oil and gas, a first seal provided at a second end of the cylinder to prevent oil and gas leakage while allowing penetration of the piston, and a second seal provided inside the cylinder to isolate the oil and gas from each other.

It is another aspect of the present invention to provide a refrigerator comprising a cabinet, a refrigerator door hinged to an open side of the cabinet, and an automatic door opening and closing apparatus including a first rotating shaft to rotatably and hingedly connect the door to the cabinet, and a damping member to allow the door to be automatically opened or closed, wherein the automatic door opening and closing apparatus may further include a second rotating shaft to rotatably connect the damping member to the door, a damper unit including a link member having a first end coupled to the damping member and a second end coupled to the second rotating shaft; and a supporting unit provided at one side thereof with the second rotating shaft to be rotatably coupled to the second end of the link member, and at the other side thereof with a coupling hole to allow the first rotating shaft to be rotatably inserted therein.

The link member may have a bent portion, extending from the second end thereof by a length corresponding to a distance between the first rotating shaft and the second rotating shaft, to thereby rotate the door by an opening angle larger than 90°.

The damper unit may further include a casing, having at least three sides, to protect the damper unit from external force, and a door hinge may be coupled to a surface of the casing, the first rotating shaft being provided at one side of the door hinge.

The door hinge may take the form of a bent plate having a first surface coupled to an upper surface of the casing and a second surface coupled to a lateral surface of the casing to thereby prevent the droop thereof due to the weight of the refrigerator door.

The door hinge may have two pin holes, and a latch pin to be selectively inserted in one of the two pin holes to thereby rotate the refrigerator door at different opening angles.

The casing may include a support plate provided at an open lower surface thereof to reinforce a strength of the casing, the support plate having coupling holes for the coupling of an adjustor bolt to adjust the installation height of the refrigerator cabinet.

The damping member may include a cylinder to contain oil and gas, a cap to close a first end of the cylinder, a piston to compress or decompress the oil and gas, a first seal provided at a second end of the cylinder to prevent oil and gas leakage while allowing penetration of the piston, and a second seal provided inside the cylinder to isolate the oil and gas from each other.

It is a further aspect of the present invention to provide an automatic door opening and closing apparatus usable with a refrigerator including a cabinet and a refrigerator door hinged to an open side of the cabinet, the opening and closing apparatus comprising a first rotating shaft to rotatably connect the door to the cabinet, and a damper unit to allow the door to be automatically opened or closed, wherein the automatic door opening and closing apparatus may further comprise a second rotating shaft to rotatably connect the damper unit to the door, the damper unit may include a damping member having a piston, and a link member to connect the piston to the second rotating shaft, and the link member may have a bent portion, extending from a first end thereof by a length corresponding to a distance between the first rotating shaft and the second rotating shaft, to thereby rotate the door to a predetermined opening angle.

The opening and closing apparatus may further comprise a first supporting unit coupled to the cabinet, the first rotating shaft being provided at one side of the first supporting unit, and a second supporting unit coupled to the refrigerator door, the second supporting unit being provided at one side thereof with the second rotating shaft to be rotatably coupled to the first end of the link member, and at the other side thereof with a coupling hole to allow the first rotating shaft to be rotatably inserted therein.

The first supporting unit may have a latch pin located close to the first rotating shaft to be caught by one side of the second supporting unit to thereby adjust the opening angle of the door, and first and second pin holes for the selective fastening of the latch pin, and the latch pin may be inserted in the first pin hole to rotate the door by a first angle, or may be inserted in the second pin hole to rotate the door by a second angle different from the first angle.

The damping member may include a cylinder to contain oil and gas, a cap to close a first end of the cylinder, a piston to compress or decompress the oil and gas, a first seal provided at a second end of the cylinder to prevent oil and gas leakage while allowing penetration of the piston, and a second seal provided inside the cylinder to isolate the oil and gas from each other.

It is a still another aspect of the present invention to provide a refrigerator comprising a cabinet, a refrigerator door hinged to an open side of the cabinet, a first rotating shaft to rotatably and hingedly connect the door to the cabinet, and a damper unit to allow the door to be automatically opened or closed, wherein the refrigerator may further comprise a second rotating shaft to rotatably connect the damper unit to the door, the damper unit may include a damping member, and a link member to connect the damping member to the second rotating shaft, when the door is opened by approximately 90° to align the second rotating shaft, first rotating shaft, and an end of the link member connected to the damping member on a straight line, the door may temporarily stop to rotate, when the door is opened by an angle larger than 90° to form an obtuse angle between imaginary lines diverging from the first rotating shaft to both the second rotating shaft and the end of the link member connected to the damping member, the door may be forced to be opened, and when the door is opened by an angle smaller than 90°, to form an angle larger than 180° between the second rotating shaft, the first rotating shaft and the end of the link member connected to the damping member, the door may be forced to be closed.

The damping member may include a cylinder, damping materials including oil and gas inside the cylinder, and a piston having a first end to compress or decompress the damping materials and a second end connected to the link member, when the door is opened, the first end of the piston may advance into the cylinder of the damping member to compress the damping materials, when the door is opened by approximately 90° and is temporarily stopped, the piston may compress the damping materials to the maximum extent, and when the door is opened by an angle smaller or larger than 90°, the piston may be retreated from the cylinder by a restoration force of the damping materials to thereby allow the door to be automatically and smoothly closed or opened.

The link member may be bent from a point connected to the second rotating shaft by a distance, corresponding to a distance between the first rotating shaft and the second rotating shaft, to thereby rotate the door by an angle larger than 90°, a bent portion of the link member being caught by the first rotating shaft when the door is opened by a maximum angle.

The damper unit may further include a casing having at least three sides, a first supporting unit may be coupled to a surface of the casing, the first rotating shaft being provided at the first supporting unit, and a second supporting unit may be coupled to the first supporting unit, the second supporting unit having the second rotating shaft, and a coupling hole to allow the first rotating shaft to be rotatably inserted therein.

A support plate may be provided at a lower surface of the casing and may have coupling holes for the coupling of an adjustor bolt to adjust the installation height of the cabinet.

It is yet another aspect of the present invention to provide an automatic door opening and closing apparatus usable with a refrigerator including a cabinet and a refrigerator door hinged to an open side of the cabinet, the opening and closing apparatus comprising a first rotating shaft to rotatably and hingedly connect the door to the cabinet, and a damper unit to allow the door to be automatically opened or closed, wherein the automatic door opening and closing apparatus may further comprises a second rotating shaft affixed to the door and rotatably coupled to the damper unit, the damper unit may be installed at an upper and/or lower portion of the cabinet in perpendicular to the door, the damper unit having a damping member, a link member, and a piston, the piston may have a first end coupled to the damping member and a second end coupled to the link member, and the link member may have a first end coupled to the second end of the piston and a second end coupled to the second rotating shaft.

The link member may have a bent portion, extending from the second end thereof by a length corresponding to a distance between the first rotating shaft and the second rotating shaft, to thereby rotate the door by an angle larger than 90°, the bent portion being caught by the first rotating shaft when the door is opened by a predetermined angle.

The damper unit may further have a casing, having at least three sides, to protect the damper unit from external force, the damping member may be affixed to the casing, and the piston may be connected to the damping member at an opposite side of the first rotating shaft.

The damping member may be a gas spring containing oil and gas layers therein.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, of which:

FIG. 1 is a perspective view showing the outer appearance of a refrigerator according to a preferred embodiment of the present invention;

FIG. 2 is a perspective view showing the coupling relationship between a refrigerator door and an automatic door opening and closing apparatus according to a preferred embodiment of the present invention;

FIG. 3 is a bottom perspective view of the automatic door opening and closing apparatus of FIG. 2;

FIG. 4 is a perspective view of a damping member included in the automatic door opening and closing apparatus of FIG. 2;

FIG. 5 is a sectional view showing the operation of the automatic door opening and closing apparatus when a refrigerator door is opened by an acute angle;

FIG. 6 is a sectional view showing the operation of the automatic door opening and closing apparatus when the refrigerator door is opened by approximately 90°;

FIG. 7 is a sectional view showing the operation of the automatic door opening and closing apparatus when the refrigerator door is opened by an angle larger than 90° and smaller than a maximum opening angle; and

FIG. 8 is a sectional view showing the operation of the automatic door opening and closing apparatus when the refrigerator door is opened by the maximum opening angle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiment of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiment is described below to explain the present invention by referring to the figures.

FIG. 1 is a perspective view showing the outer appearance of a refrigerator according to a preferred embodiment of the present invention.

Referring to FIG. 1, the refrigerator includes a cabinet 1 having a rectangular cross section. The cabinet 1 is opened at a front side thereof to store or remove foods from the cabinet 1. Doors 2 and 5 are hinged to the open front side of the cabinet 1. The refrigerator according to the embodiment of the present embodiment is a two-door refrigerator having left and right doors, and internally defines a freezing chamber 4 and a refrigerating chamber (not shown). The inner side of each door is provided with racks 3 to store small foods, beverage containers, etc, and the outer side of the door is provided with a handle for convenient door opening or closing.

The refrigerator includes automatic door opening and closing apparatuses 6 that are mounted at lower ends of opposite lateral walls of the cabinet 1 where the doors 2 and 5 are connected to the cabinet 1 by means of hinges (not shown). It should be understood that the automatic door opening and closing apparatuses 6 may be mounted at upper ends of the opposite lateral walls of the cabinet 1.

FIG. 2 is a perspective view showing the coupling relationship between the refrigerator door and automatic door opening and closing apparatus according to a preferred embodiment of the present invention. Prior to explaining the coupling relationship, it should be noted that the below description will deal with only one of the doors and the associated door opening and closing apparatus because the two doors of the refrigerator are identical to each other and the two automatic door opening and closing apparatuses are identical to each other.

The automatic door opening and closing apparatus according to the preferred embodiment of the present invention includes a damper unit 10, a first supporting unit 20, and a second supporting unit 30. Explaining first the second supporting unit 30, it takes the form of a plate attached to an end of the lower surface of the door 5. The second supporting unit 30 has a second rotating shaft 31 located at one side thereof to be connected to the door 5 via the upper portion thereof vertically protruding from the second supporting unit 30, a coupling hole 32 formed at the other side thereof, and a stopper 33 protruding downward beneath the coupling hole 32. The lower portion of the second rotating shaft 31, protruding downward from the second supporting unit 30, is rotatably inserted through a coupling hole 16 a formed at a link member 16 of the damper unit 10.

The first supporting unit 20, coupled with the second supporting unit 30, includes a flat portion 21 to be coupled with a surface of a casing 11 included in the damper unit 10, a lateral portion 22 formed by bending the flat portion 21, and couplers 23 to be coupled to a lateral surface of the casing 11. The first supporting unit 20 further includes a first rotating shaft 24, first and second pin holes 25 and 26, and a latch pin 27.

The first rotating shaft 24 protrudes upward and downward from the flat portion 21 of the first supporting unit 20 by predetermined lengths. Although it is preferable to integrally form the first rotating shaft 24 with the flat portion 21, the first rotating shaft 24 may be inserted through a hole of the flat portion 21. The upper portion of the first rotating shaft 24, protruding upward from the flat portion 21, is connected to the door 5 by passing through the coupling hole 32 of the second supporting unit 30. The lower portion of the first rotating shaft 24, protruding downward from the flat portion 21, is used to catch a bent portion of the link member 16.

The first and second pin holes 25 and 26 are formed at the flat portion 21 of the first supporting unit 20 and have inner threads for the selective fastening of the latch pin 27. The latch pin 27 has outer threads 27 a to mate with the inner threads of the pin hole 25 or 26. The latch pin 27 is selectively inserted through one of the pin holes 25 and 26 so that the door 5 is opened by 90° or 135°, which is a maximum opening angle proposed in the present embodiment. The reason why the opening angle of the door 5 is limited to 90° is to prevent damage of the door 5 when the refrigerator is installed close to a room wall surface. The latch pin 27, inserted in one of the pin holes 25 and 26, is caught by the stopper 33 of the second supporting unit 30 in a rotated and opened state of the door.

The second rotating shaft 31 of the second supporting unit 30 partially protrudes downward from the second supporting unit 30 to be inserted through the coupling hole 16 a of the link member 16. The coupling hole 32 of the second supporting unit 30 is inserted around the first rotating shaft 24 of the first supporting unit 20. The stopper 33, provided beneath the coupling hole 32, catches the latch pin 27 to restrict the opening angle of the door 5 to 90° or the maximum opening angle of 135°.

The second supporting unit 30 is rotatably coupled to the first supporting unit 20 as the upper portion of the first rotating shaft 24, protruding upward from the flat portion 21, is inserted through the coupling hole 32 of the second supporting unit 30.

The damper unit 10 is coupled to the rear side of the first supporting unit 20. The damper unit 10 includes a casing 11 defining the outer appearance of the damper unit 10. The casing 11 is formed by bending a metal plate to have an approximately box shape. The box shaped metal casing 11 provides the damper unit 10, mounted at the bottom of the refrigerator at a connecting portion between the door 5 and the cabinet 1, with a sufficient structural strength to resist the weight of the refrigerator and other external force, thereby preventing damage thereof. In the present embodiment, the casing 11 has an open lower side to provide convenient exchange or repair as well as easy operation of a damping member or link member mounted inside the casing 11.

The first supporting unit 20 is coupled at the flat portion 21 thereof to an upper surface 11 a of the casing 11. As stated above, the flat portion 21 of the first supporting unit 20 is provided with the first rotating shaft 24 inserted through the coupling hole 32 of the second supporting unit 30, and provided with the first and second pin holes 25 and 26 for the selective fastening of the latch pin 27.

The first supporting unit 20 is also coupled at the lateral portion 22 thereof to a lateral surface 11 b of the casing 11 by means of the couplers 23. As shown in FIG. 2, the first rotating unit 20 is located beneath the door 5 and is affected by the weight of the door 5. To prevent the droop of the first supporting unit 20 due to the weight of the door 5, it is preferable that the first supporting unit 20 has the lateral portion 22 formed by bending a metal plate and the lateral portion 22 is coupled to the lateral surface 11 b of the casing 11. In the embodiment of the present invention, the lateral portion 22 is divided into two parts based on a center slot so that one of the parts is bolted and the other part is welded to the lateral surface 11 b of the casing 11, but is not limited thereto, and other various coupling methods may be employed. It should be noted that the use of the coupler portion is only optional, and the first supporting unit 20 may be coupled to the casing 11 by means of only the flat portion.

In summary, the first supporting unit 20 is coupled to the damper unit 10 as the flat portion 21 and lateral portion 22 thereof are coupled to the upper surface 11 a and lateral surface 11 b of the damper unit 10. Of course, because the use of the lateral portion 22 is optional to prevent the droop of the first supporting unit 20, the first supporting unit 20 may be coupled to the damper unit 10 using only the flat portion 21 thereof.

Meanwhile, the second supporting unit 30 is coupled to the damper unit 10 as the second rotating shaft 31 thereof is rotatably inserted through the coupling hole 16 a of the link member 16. In the present embodiment, the casing 11 of the damper unit 10 and the first supporting unit 20 are affixed to the cabinet (not shown) of the refrigerator, while the second supporting unit 30 is affixed to the door 5 while being coupled with the first rotating shaft 24 of the first supporting unit 20 and the coupling hole 16 a of the link member 16 to thereby be rotatable relative to the cabinet (not shown).

FIG. 3 is a bottom perspective view of the automatic door opening and closing apparatus of FIG. 2. Referring to FIG. 3, a damping member 12 is obliquely disposed within the casing 11. One end of the damping member 12 is reciprocably coupled to a piston 14 by means of a first coupler 13. In the present embodiment, the damping member 12 is a type of gas spring to attenuate shock applied thereto as oil and gas layers defined therein are compressed and to enable soft closing operation of the door 5 by virtue of a restoration force of the oil and gas layers. The gas spring according to the embodiment of the present invention requires no inner spring or air containing compensator, eliminating generation of operational noise.

The piston 14 is a metal rod having seals (not shown) at opposite ends thereof. The piston 14 serves to compress or decompress the gas and oil layers included in the damping member 12. A first end of the piston 14 is coupled to the damping member 12 as stated above, and a second end of the piston 14 is affixed to one end of the link member 16 by rivets, etc. so as not to move relative to the link member 16. The affixed second end of the piston 14 is called as a second coupler 15 for convenience of explanation.

The link member 16 is coupled at a first end thereof to the second end of the piston 14, and a second end of the link member 16 has the coupling hole 16 a to allow the second rotating shaft 31 of the second supporting unit 30 to be inserted therein. The link member 16 is made of metal. The link member 16 is bent in the vicinity of the second end thereof, to be coupled with the second rotating shaft 31, by a predetermined angle. The bent portion of the link member 16 has a length corresponding to a distance between the first rotating shaft 24 and the second rotating shaft 31. The link member 16 configured as stated above serves to enable the door 5 to rotate by an angle more than 90°. As the bent portion of the link member 16 is caught by the downwardly protruding portion of the first rotating shaft 24, the opening operation of the door 5 is stopped. In the embodiment of the present invention, the door 5 is opened to the maximum opening angle of 1350, but the angle may be varied depending on product designs.

A support plate 17 is provided in the vicinity of the coupler portion 23 of the first supporting unit 20 to extend between opposite lateral edges of the casing 11. The support plate 17 is formed by bending opposite ends of a metal band and affixing the bent ends to the casing 11. The support plate 17 serves to reinforce the strength of the casing 11 to thereby prevent the casing 11 from widening. Two coupling holes 17 a are formed at the support plate 17 for the selective coupling of an adjustor bolt 18. The adjustor bolt 18 is used to adjust the height of the cabinet bottom in order to horizontally level it upon initial installation of the refrigerator.

The adjustor bolt 18 has a flat head portion, and is inserted through one of the coupling holes 17 a having inner threads to adjust the height of the cabinet bottom by increasing or decreasing the number of fastening turns thereof. In the present embodiment, the reason why the support plate 17 has two coupling holes 17 a is to enable the automatic door opening and closing apparatus of the present invention to be compatibly used in both the left and right doors of the two-door refrigerator.

FIG. 4 is a perspective view showing the damping member of the automatic door opening and closing apparatus of FIG. 2. The damping member 12 according to the embodiment of the present invention includes a cylinder 12 a, a cap 12 b provided at one end of the cylinder 12 a to prevent the leakage of gas and oil contained in the cylinder 12 a, a first seal 12 c provided at the other end of the cylinder 12 a to prevent gas and oil leakage while allowing reciprocating penetration of the piston 14, and a second seal 12 d provided inside the cylinder 12 a to prevent mixing of oil and gas layers inside the cylinder 12 a.

The piston 14 is inserted into one end of the cylinder 12 a by passing through a hole perforated in the first seal 12 c to thereby rotatably reciprocate within the cylinder 12 a. As the piston 14 reciprocates within the cylinder 12 a, a leading end 14 a of the piston 14 acts to compress oil and gas layers inside the cylinder 12 a via forward movement or is retreated by a restoration force of the oil and gas layers. The cap 12 b and the first seal 12 c as well as the piston end 14 a are sized to come into close contact with the inner circumference of the cylinder 12 a to prevent oil and gas leakage.

The cap 12 b and the first seal 12 c are fixed at opposite ends of the cylinder 12 a so as not to move, whereas the piston end 14 a and the second seal 12 d are reciprocable within the cylinder 12 a by using the pressure of the oil and gas layers. In the embodiment of the present invention, oil is filled between the piston end 14 a and the second seal 12 d, and gas is filled between the second seal 12 d and the cap 12 b, or vice ver sa.

Different from general gas springs mainly using nitrogen gas, the embodiment of the present invention uses compressed nitrogen gas to thereby reciprocate the piston 14 over a sufficient distance without using an elastic member, such as a spring or compensator.

Now, the operation and effects of the automatic door opening and closing apparatus according to the present invention will be explained with reference to FIGS. 5 to 8.

FIG. 5 is a sectional view showing the operation of the automatic door opening and closing apparatus when the door is opened by an acute angle, for example, approximately 60°. By comparing FIG. 5 with FIG. 3 that shows the closed state of the door 5, it can be clearly understood that the piston 14 is inserted into the damping member 12 by a sufficient length to compress the damping member 12. That is, when the door 5 is closed, the piston 14 applies no pressure force to the damping member 12, whereas, if the door 5 is gradually opened, the link member 16 rotates along with the second supporting unit 30 connected to the door 5, thereby causing the piston 14 to reciprocate and be inserted into the damping member 12 to thereby compress oil and gas as damping materials (not shown).

In this case, an angle θ formed by imaginary lines diverging from the first rotating shaft 24 to both the second coupler 15, as a connector between the link member 16 and the piston 14, and the second rotating shaft 31, is more than 180°. In such an angle state, if no further opening force is applied to the door 5, the door 5 is affected by a restoration force of damping materials filled in the damping member 12 to be closed, thereby being automatically closed.

FIG. 6 is a sectional view showing the operation of the automatic door opening and closing apparatus when the door is opened by approximately 90°. As the door 5 is opened, the damping member 12 is gradually compressed to the maximum extent by the piston 14. In this case, the angle θ between the second coupler 15, first rotating shaft 24 and second rotating shaft 31 is 180°. That is, the second coupler 15, first rotating shaft 24 and second rotating shaft 31 are located on a straight line, and the door is in a temporarily stopped state because forces acting to the respective elements are the same as one another to thereby be offset.

If the door 5 is forced to rotate in a direction so that the second coupler 15, first rotating shaft 24 and second rotating shaft 31 deviate from the straightly aligned state, the damping member 12, in a maximally compressed state, operates to open or close the door 5 by virtue of the restoration force of the damping materials therein. When the door 5 is opened, the opening angle of the door 5 is approximately 90-108° although the opening angle may be varied according to design values, such as an angle that the damping member 12 is affixed to the casing 11, and the size and arrangement of other members.

FIG. 7 is a sectional view showing the operation of the automatic door opening and closing apparatus when the door is opened by an angle larger than 90° and smaller than the maximum opening angle. As shown in FIG. 7, the angle θ between the second coupler 15, first rotating shaft 24 and second rotating shaft 31 is less than 180°. In this case, the piston 14 is pushed to the left side of FIG. 7 by the restoration force of the damping member 12. Thereby, the link member 16 connected to the piston 14 is rotated to thereby rotate the second supporting unit 30, resulting in the automatic opening of the door 5 to the maximum opening angle.

The maximum opening angle of the door 5 according to the embodiment of the present invention is approximately 135°, but is not limited thereto and can be varied. That is, whether the latch pin 27 is inserted to the first pin hole 25 or second pin hole 26, the maximum opening angle of the door 5 can be adjusted to 90° or 135°. Further, according to the formed positions of the pin holes 25 and 26, the opening angle of the door 5 is freely adjustable. It was previously described that the stopper 33 of the second supporting unit 30 catches the latch pin 27 to thereby prevent the further opening of the door 5.

In the case of FIG. 7, the angle between the second coupler 15, first rotating shaft 24 and second rotating shaft 31 is an obtuse angle of 135-180°. In such an angle state, the door 5 is forced to be opened to the maximum opening angle.

FIG. 8 is a sectional view showing the operation of the automatic door opening and closing apparatus when the door is opened to the maximum opening angle. If the door 5 is opened to the maximum angle, no pressure force is applied to the damping member 12 in the same manner as the case that the door 5 is closed. Thus, the piston 14 is wholly exposed to the outside of the damping member 12. The maximum opening angle can be achieved only when the stopper 33 of the second supporting unit 30 catches the latch pin 27 inserted in the second pin hole 26. In this case, the angle θ between the second coupler 15, first rotating shaft 24, and second rotating shaft 31 is an obtuse angle of 90-180°.

In the present invention, the door 5 can operate smoothly without generation of noise via the compression and restoration of oil and gas layers inside the damping member 12. Further, the door 5 can be completely and tightly closed because the damping member 12 always ensures accurate compression and restoration operations, thereby having no risk of cold air loss due to the incomplete closing of the door 5.

As apparent from the above description, the present invention provides an automatic door opening and closing apparatus and a refrigerator having the same having a simplified and strong damper unit and other structures connected thereto, thereby achieving effective and smooth operation of a refrigerator door with a low effort. By allowing the refrigerator door to be automatically opened or closed when the opening angle of the refrigerator is in a predetermined range, the automatic door opening and closing apparatus of the present invention can provide satisfactory use of products.

Further, as a result of using a gas spring as a damping member, the automatic door opening and closing apparatus and the refrigerator having the same generate no noise, achieving quiet operation.

Furthermore, the automatic door opening and closing apparatus of the present invention achieves accurate opening and closing operations of a refrigerator door, thereby eliminating the risk of cold air leakage due to incomplete closing of the door.

Although embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. An automatic door opening and closing apparatus usable with a refrigerator including a cabinet and a refrigerator door hinged to an open side of the cabinet, the opening and closing apparatus comprising: a first rotating shaft to rotatably connect the refrigerator door to the cabinet; a damper unit to allow the refrigerator door to be automatically opened or closed; and a second rotating shaft to rotatably connect the damper unit to the refrigerator door to allow the refrigerator door to be automatically opened or closed by the damper unit according to an opening degree of the door, wherein: the damper unit includes a damping member and a link member; and the link member has a first end coupled to the damping member, and a second end coupled to the second rotating shaft.
 2. The apparatus according to claim 1, wherein the damper unit further includes a casing, having at least three sides, to protect the damper unit from external force.
 3. The apparatus according to claim 1, wherein the link member has a bent portion, extending from the second end thereof by a length corresponding to a distance between the first rotating shaft and the second rotating shaft, to thereby rotate the door by an opening angle larger than 90°.
 4. The apparatus according to claim 2, further comprising a first supporting unit coupled to a surface of the casing, the first rotating shaft being provided at one side of the first supporting unit.
 5. The apparatus according to claim 4, wherein the first supporting unit includes a bent plate having a first surface coupled to an upper surface of the casing and a second surface coupled to a lateral surface of the casing to thereby prevent the droop thereof due to the weight of the door.
 6. The apparatus according to claim 4, further comprising a second supporting unit provided at one side thereof with the second rotating shaft to be rotatably coupled to the second end of the link member, and at the other side thereof with a coupling hole to allow the first rotating shaft to be rotatably inserted therein.
 7. The apparatus according to claim 4 or 6, wherein: the first supporting unit has a latch pin located close to the first rotating shaft to be caught by one side of the second supporting unit to thereby adjust the opening angle of the door, and first and second pin holes for the selective fastening of the latch pin; and the latch pin is inserted in the first pin hole to rotate the door by an opening angle larger than 90°, or is inserted in the second pin hole to rotate the door by approximately 90°.
 8. The apparatus according to claim 7, wherein the second supporting unit has a stopper in the vicinity of the coupling hole thereof to catch the latch pin inserted in the first or second pin hole to thereby adjust the opening angle of the door.
 9. The apparatus according to claim 2, wherein a support plate is provided at a lower surface of the casing and has coupling holes for the coupling of an adjustor bolt to adjust the installation height of the cabinet.
 10. The apparatus according to claim 1, wherein the damping member includes: a cylinder to contain oil and gas; a cap to close a first end of the cylinder; a piston to compress or decompress the oil and gas; a first seal provided at a second end of the cylinder to prevent oil and gas leakage while allowing penetration of the piston; and a second seal provided inside the cylinder to isolate the oil and gas from each other.
 11. A refrigerator comprising a cabinet, a refrigerator door hinged to an open side of the cabinet, and an automatic door opening and closing apparatus including a first rotating shaft to rotatably and hingedly connect the door to the cabinet, and a damping member to allow the door to be automatically opened or closed, wherein the automatic door opening and closing apparatus further includes: a second rotating shaft to rotatably connect the damping member to the door; a damper unit including a link member having a first end coupled to the damping member and a second end coupled to the second rotating shaft; and a supporting unit provided at one side thereof with the second rotating shaft to be rotatably coupled to the second end of the link member, and at the other side thereof with a coupling hole to allow the first rotating shaft to be rotatably inserted therein.
 12. The refrigerator according to claim 11, wherein the link member has a bent portion, extending from the second end thereof by a length corresponding to a distance between the first rotating shaft and the second rotating shaft, to thereby rotate the door by an opening angle larger than 90°.
 13. The refrigerator according to claim 11, wherein: the damper unit further includes a casing, having at least three sides, to protect the damper unit from external force; and a door hinge is coupled to a surface of the casing, the first rotating shaft being provided at one side of the door hinge.
 14. The refrigerator according to claim 13, wherein the door hinge takes the form of a bent plate having a first surface coupled to an upper surface of the casing and a second surface coupled to a lateral surface of the casing to thereby prevent the droop thereof due to the weight of the refrigerator door.
 15. The refrigerator according to claim 13, wherein the door hinge has two pin holes, and a latch pin to be selectively inserted in one of the two pin holes to thereby rotate the refrigerator door at different opening angles.
 16. The refrigerator according to claim 13, wherein the casing includes a support plate provided at an open lower surface thereof to reinforce a strength of the casing, the support plate having coupling holes for the coupling of an adjustor bolt to adjust the installation height of the refrigerator cabinet.
 17. The refrigerator according to claim 11, wherein the damping member includes: a cylinder to contain oil and gas; a cap to close a first end of the cylinder; a piston to compress or decompress the oil and gas; a first seal provided at a second end of the cylinder to prevent oil and gas leakage while allowing penetration of the piston; and a second seal provided inside the cylinder to isolate the oil and gas from each other.
 18. An automatic door opening and closing apparatus usable with a refrigerator including a cabinet and a refrigerator door hinged to an open side of the cabinet, the opening and closing apparatus comprising a first rotating shaft to rotatably connect the door to the cabinet, and a damper unit to allow the door to be automatically opened or closed, wherein: the automatic door opening and closing apparatus further comprises a second rotating shaft to rotatably connect the damper unit to the door; the damper unit includes a damping member having a piston, and a link member to connect the piston to the second rotating shaft; and the link member has a bent portion, extending from a first end thereof by a length corresponding to a distance between the first rotating shaft and the second rotating shaft, to thereby rotate the door to a predetermined opening angle.
 19. The apparatus according to claim 18, further comprising: a first supporting unit coupled to the cabinet, the first rotating shaft being provided at one side of the first supporting unit; and a second supporting unit coupled to the refrigerator door, the second supporting unit being provided at one side thereof with the second rotating shaft to be rotatably coupled to the first end of the link member, and at the other side thereof with a coupling hole to allow the first rotating shaft to be rotatably inserted therein.
 20. The apparatus according to claim 19, wherein: the first supporting unit has a latch pin located close to the first rotating shaft to be caught by one side of the second supporting unit to thereby adjust the opening angle of the door, and first and second pin holes for the selective fastening of the latch pin; and the latch pin is inserted in the first pin hole to rotate the door by a first angle, or is inserted in the second pin hole to rotate the door by a second angle different from the first angle.
 21. The apparatus according to claim 20, wherein the damping member includes: a cylinder to contain oil and gas; a cap to close a first end of the cylinder; a piston to compress or decompress the oil and gas; a first seal provided at a second end of the cylinder to prevent oil and gas leakage while allowing penetration of the piston; and a second seal provided inside the cylinder to isolate the oil and gas from each other.
 22. A refrigerator comprising a cabinet, a refrigerator door hinged to an open side of the cabinet, a first rotating shaft to rotatably and hingedly connect the door to the cabinet, and a damper unit to allow the door to be automatically opened or closed, wherein: the refrigerator further comprises a second rotating shaft to rotatably connect the damper unit to the door; the damper unit includes a damping member, and a link member to connect the damping member to the second rotating shaft; when the door is opened by approximately 90° to align the second rotating shaft, first rotating shaft, and an end of the link member connected to the damping member on a straight line, the door temporarily stops to rotate; when the door is opened by an angle larger than 90° to form an obtuse angle between imaginary lines diverging from the first rotating shaft to both the second rotating shaft and the end of the link member connected to the damping member, the door is forced to be opened; and when the door is opened by an angle smaller than 90°, to form an angle larger than 180° between the second rotating shaft, the first rotating shaft and the end of the link member connected to the damping member, the door is forced to be closed.
 23. The refrigerator according to claim 22, wherein: the damping member includes a cylinder, damping materials including oil and gas inside the cylinder, and a piston having a first end to compress or decompress the damping materials and a second end connected to the link member; when the door is opened, the first end of the piston advances into the cylinder of the damping member to compress the damping materials; when the door is opened by approximately 90° and is temporarily stopped, the piston compresses the damping materials to the maximum extent; and when the door is opened by an angle smaller or larger than 90°, the piston is retreated from the cylinder by a restoration force of the damping materials to thereby allow the door to be automatically and smoothly closed or opened.
 24. The refrigerator according to claim 22, wherein the link member is bent from a point connected to the second rotating shaft by a distance, corresponding to a distance between the first rotating shaft and the second rotating shaft, to thereby rotate the door by an angle larger than 90°, a bent portion of the link member being caught by the first rotating shaft when the door is opened by a maximum angle.
 25. The refrigerator according to claim 22, wherein: the damper unit further includes a casing having at least three sides; a first supporting unit is coupled to a surface of the casing, the first rotating shaft being provided at the first supporting unit; and a second supporting unit is coupled to the first supporting unit, the second supporting unit having the second rotating shaft, and a coupling hole to allow the first rotating shaft to be rotatably inserted therein.
 26. The refrigerator according to claim 25, wherein a support plate is provided at a lower surface of the casing and has coupling holes for the coupling of an adjustor bolt to adjust the installation height of the cabinet.
 27. An automatic door opening and closing apparatus usable with a refrigerator including a cabinet and a refrigerator door hinged to an open side of the cabinet, the opening and closing apparatus comprising a first rotating shaft to rotatably and hingedly connect the door to the cabinet, and a damper unit to allow the door to be automatically opened or closed, wherein: the automatic door opening and closing apparatus further comprises a second rotating shaft affixed to the door and rotatably coupled to the damper unit; the damper unit is installed at an upper and/or lower portion of the cabinet in perpendicular to the door, the damper unit having a damping member, a link member, and a piston; the piston has a first end coupled to the damping member and a second end coupled to the link member; and the link member has a first end coupled to the second end of the piston and a second end coupled to the second rotating shaft.
 28. The apparatus according to claim 27, wherein the link member has a bent portion, extending from the second end thereof by a length corresponding to a distance between the first rotating shaft and the second rotating shaft, to thereby rotate the door by an angle larger than 90°, the bent portion being caught by the first rotating shaft when the door is opened by a predetermined angle.
 29. The apparatus according to claim 27, wherein: the damper unit further has a casing, having at least three sides, to protect the damper unit from external force; the damping member is affixed to the casing; and the piston is connected to the damping member at an opposite side of the first rotating shaft.
 30. The apparatus according to claim 27, wherein the damping member is a gas spring containing oil and gas layers therein. 